Control mechanism



March 7, 1944. c. A. BREWER CONTROL MECHANISM Origihal Filed May 11. 1954 2 Sheets-Sheet l INVENTOR.

M? 16M ATTo pEys.

III

March 7, 1944. c. A. BREWER Re. 22,451

CONTROL MEOHANI SM Original F iled May'll, 1954 2 Sheets-SheefQ 1NVENTOR flaw/15M BYz Arronuzv -nism,

Reissued Mar. 7, 1944 Re. 22,451 v con'mor. nmcnmsm Charles A. Brewer.

Noroton Heights, Conm, assignor of one-half to Philip J.

Km- A Y men Original No. 2,225,882, dated December 24, 1940,

Serial No. 725,187,

for reissue October 2,

19 Claims.

This invention relates to clutch control mechaand more particularly to fluid pressure power means for actuating and controlling the clutch of an automotive vehicle.

This is an application for the reissuance of my Patent No. 2,225,682, issued December 24, 1940, for improvements in Control mechanism.

One of the objects of the present invention is to provide novel power and/or manually operated means for disengaging and engaging the friction surfaces of a clutch, said means being so con- May 11, 1934.

1942, Serial No.

Application 460,575

structed that engagement of said surfaces may be controlled in a manner to simulate expert manual operation of theclutch.

,Another object of the invention is to provide novel vacuum clutch control means which are so constructed as to facilitate manual operation of the clutch in the event of a failure of the power elements of said control means.

Another object is to provide novel control means for the power clutch actuating apparatus,

whereby the movement of the clutch surfaces by said apparatus may be manually controlled to secure any desired movement of the clutch surfaces.

A further object is to provide power clutch control mechanism of the type wherein the clutch surfaces are moved toward and into engagement at a varying rate of speed, said mechanism embodying novel means for rendering the automatic control of the engaging movement ineffective, whereby said engaging movement may be accelerated or retarded at the will of the operator.

Another object is to provide novel valve mechanism for initiating the disengaging and engaging movement of the clutch parts, said valve mechanism being adapted to be actuated either manually or by power means.

The above and other objects and advantages of the invention will appear more fully hereafter in the detailed description which is to be read in connection with the accompanying drawings. It-will be understood, however, that said drawings are for purposes of illustration only and are not ,designed as a definition of the limits of the invention, reference bein had for this purpose to the appended claims. In the drawings,

Fig. 1 is a side elevation, partly in section and with parts broken away, illustrating one embodiment of the present invention;

Fig. 2 is a sectional view taken substantially on line 2-2 of Fig. 1, a portion of the mechanism being shown in elevation and with an electrical control device attached thereto;

Fig. 3 is a sectional detail taken on the line 3-3 of Fig. 2;

Fig. 4 is a top plan view illustrating one element of the control mechanism;

Fig. 5 is a sectional detail view taken tially on the line 5-5 of Fig. 2;

Figs. 6, 7 and 8 are detail views showing various shapes that may be given to a portion of one of the control members;

Fig. 9 is a side elevation, with parts broken away, or a second embodiment of the invention, the power unit per se being similar to that shown in Fig. 1; and

Fig.10 is a top plan view of a third embodiment of the invention.

Referring to the embodiment of the invention illustrated in Fig. 1, I l is a portion of a lever operatively associated with a vehicle clutch (not shown) of any suitable type. As is understood in the art, pivotal movement of lever II in an anticlockwise direction is effective to move the friction surfaces of the clutch to disengaged, or inopsubstanto lever II and floor boards l2, may be provided to yieldingly hold the upper end of said lever in operative engagement with the power device and its control mechanism, to be described hereafter, and to hold the lower end of said lever in such a position to relieve wear of the clutch trunnion bearing.

. The power unit for actuating the clutch lever is of the vacuum type, in the form shown, and comprises a cylinder I 0 (Figs. 1, 9 and 10) having therein a piston l5 attached to a piston rod I8 which is guided in its reciprocating movement by means of a cylinder mounting bracket Il secured in any suitable manner below and closely adjacent the fioor boards l2. Extending transversely through the outer end of piston rod I6 is a pin l8 adapted to move in a groove l9 (Figs. 1 and 10) provided in bracket l1. Rollers 20 (Figs. 1 and 9) are mounted on the opposite ends of pin l8, and, preferably, lever H is bifurcated to engage the two rollers on the opposite sides of bracket l'l. It will thus be seen that movement of piston l5 to the left and downwardly, as viewed in Fig. 1, will result in rollers l8 moving lever II in an anticlockwise direction, whereby the friction surfaces of the clutch will be disengaged.

The power cylinder I4 is operativeiy connected to a suitable source of fluid power, such as the intake manifold 2| of an internal combustion engine (not shown), a pipe 22 being employed as the connection between said cylinder and manifold. when air is exhausted from the lower lefthand end of cylinder l4 through vacuum connection 22, it will be apparent that piston II and piston rod II will be moved downwardly to actuate lever ii and disengage the friction elements of the clutch.

Novel valve means are provided for controlling I the'vaeuum connection to cylinder II. To this end, the cylinder head 26 at the lower end of said cylinder is provided with an opening or pas-, sage 23 (Fig. 2) which leadsfrom the interior of the cylinder to a cylindrical passage 24 formed in an enlarged and projecting portion 26a of said cylinder head. Slidably mounted within passage 24 is a valve member 23 adapted to control a vacuum passage 21, the walls of the outer end of the latter being threaded as at 24 to receive the pipe 22. Member 26 carries a conical valve 28 adjacent one end thereof, adapted to close passage 21, and -a valve III adjacent the opposite end. Flanges 3|, having segments cut from the peripheries thereof, are integral with member 26 and serve to guide the latter during its movement in passage 24. The right-hand end of valve member 26, as viewed in Fig. 2, is provided with a rod 32 which extends into a sleeve 33 threaded into the walls of passage 24. The left-hand end of sleeve 33 is provided with a seat for valve 33 whereby the latter is adapted to close an air passage 334: formed in the left-hand end of said sleeve.

Novel means are provided for connecting valve member 26 to operating means therefor, the connecting means being such as to permit relative movement between valve member 26 and its operating means, whereby control of said valve member is subject in part to vacuum and atoms pheric pressures and inpart to manual operation. As shown, said connecting means are constituted by a barrel 34 slidably mounted within sleeve 33, the inner walls of said banal serving as a guide for the enlarged head 32:: of rod 32. A spring 35 is positioned in the left-hand end of barrel 34 to yieldingly resist relative movement between said barrel and said rod in one direction, relative movement in the other direction being resisted by means of a spring 38 positioned in the right-hand end of the barrel. The outer end of barrel 34 carries a flange 21, constituting a valve, which is held in engagement with a U-shaped member 33 V by means of a screw 3! extending into the righthand, threaded end of the barrel. Preferably, a

sealing ring 43 is interposed between valve 31 and the adjacent end of sleeve 33 in order to control the flow of air through a e 4i provided between the outer wall of the barrel and the inner wall of said sleeve. As shown in Fig. 4, a segment is cut from the outer surface of barrel 34 to provide the air passage 4 I.

Adjustably secured to U-shaped member 38, adjacent barrel 34, is a push rod 42 that is slidably mounted in a cylindrical passage 43 formed in cylinder head portion 234! and extending parallel to passage 24. A spring 44, positioned in passage 43 and surrounding a reduced portion of rod 42, is normally eflective through U-shaped member 33 to retain valve 31 in engagement with sealing ring 40, closing air passage 4|. Barrel 34 is thus yieldingly held in such a position that springs. 36 and 33 maintain valve 29 on its seat,-

passage 24, and opening 23 to exhaust the air from cylinder I4 and move piston II downwardly to disengage the clutch plates, it being noted that the upper face of said piston is always subjected to atmospheric pressure through a suitable opening in the upper cylinder head. After valve 28 is opened, valve 33 is moved onto its seat, whereby the flow of air through passage 33a is prevented. As shown, the manual means for actuating rod 42 comprises a slidably mounted rod 46 (Figs. 1, 2, 9 and 10) which extends through a suitable opening in floor boards l2 in the position occupied by the usual clutch pedal, the use of thelatter being rendered unnecessary by the present invention. The upper end of rod 46 is provided with a footpad 41 while the lower end extends through an opening 43 (Fig. 2) in the raised portion 25a of cylinder head 25, the intermediate portion of the rod being guided by bracket l1.

As shown more clearly in Figs. 2, 6, 7 and 8, the lower end of rod 46 is tapered as at 460.,

46b, 460 or 56d, the tapered portion being adaptwhereby the rods and valve member 28 occupy the position shown in Fig. 2. When rod 46 is moved downwardly, under foot pressure applied to pad 41, a suflicient distance for the cylindrical portion thereof to engage rod 42, the latter is effective through member 38, its associated elements and yielding connection 35 to open valve 29 and seat valve 30, whereupon the power unit operates to fully disengage the clutch. The only effort required by the driver to disengage the clutch is that employed in depressing rod 46 a short distance against the tension of springs 44 and 49 and the fluid pressures acting on valve member 26. When it is desired to engage the friction surfaces of the clutch, the operator releases rod 46, which is returned to normal position by means of spring 49, and spring 44 is operative to return push rod 42 and valve member 26 to normal position, whereby valve 29 closes the vacuum connection between the intake manifold and the cylinder. As valve 30 moves from its seat, passage 33a is opened and since this passage is in communication with an air passage 53 (Figs. 2, 3 and 5) air can now flow past valve 30 and through opening 23 into 'the cylinder whereupon the clutch spring is effective to return the parts to clutch engaging position.

Novel automatic means are provided for controlling movement of lever Ii from disengaged position to the engaged position shown in Fig. 1, whereby the friction surfaces of the clutch may be brought into engagement in a predetermined pose it is desirable that the first portion of the return movement of lever H be rapid, and that at the instant prior to and during engagement of the friction surfaces of the clutch, said move- ,ment of the lever be retarded. The final portion of the movement of lever I l to normal position may be rapid.

The variable return movement of piston l5 and lever II for securing prompt and yet smooth engagement of the clutch surfaces is obtained by means which comprise an arm 5| (Figs. 1 and 9) pivoted to a suitable lug provided adjacent the upper end of cylinder l4.. The upper end of arm 5| is bent inwardly and carries at its extremity a roller 52 adapted to be engaged by a cylindrical cam 53 adjustably carried by a threaded rod 54 which extends through an opening in the upper cylinder head of the power device, said opening being somewhat larger than the greatest diameter of the cam 53 to provide for free passage of air into the upper end of the cylinder. The upper end of rod 54 is secured in any suitable manner to the adjacent end of pin I5, while the lower end of said rod is attached to the upper face of piston I5, so that said rod, cam and piston move in unison.

The lower end of arm 5| (Fig. 2) is adapted to engage a cylindrical valve 55 slidably mounted in a passage 55 formed in the cylinder head portion a, said passage allel to passages 43 and 24 and connected to the latter by passage 55. A coil spring 51, positioned in passage or bore 55, maintains the valve 55 at all times in engagement with lever arm 5|. When the piston is moved downwardly to disengage the clutch, cam 53 passes beneath roller 52 imparting a pivotal movement to arm 5| without varying the operation of the device, since cylinder I4 is at this time closed to atmosphere by valve 35. clutch engaging position, cam 53 moves upwardly with piston l5 and again engages lever arm 5| just prior to the engagement of the clutch surfaces, whereupon the lower end of said lever arm is effective .to move valve 55 to the right, as viewed in Fig. 2, gradually cutting off the flow of air into passage 55 and cylinder l4 throu h ports a and 58 provided in the walls of bore 55. Pa!- sa e is provided with a branch passage 50 Figs. 3 and 5) which may be adiustably restricted by means of the bleed valve 55. For a purpose to be hereinafter described, valve 59 may I be completely closed so that the clutch surfaces will be arrested upon the closure of ports 50a and 55 by valve 55.

As is seen more clearly in Figs. 2 and 5, the left-hand end of sleeve 33 abuts against a should er formed within the walls of passage 24. Closely adjacent this shoulder, sleeve 33 is provided with an annular groove which registers with the adjacent end of passage 55. Openings 33b are formed in the sleeve in the plane of said annular groove and extend radially outward from the inner passage 33a. When valve 55 is in'the position illustrated in Figs. 2 and 3, passage 55 is in communication with the atmosphere as indicated, and air is free to flow through conuectingpassages 33a, 33b, 24 and 23 into the interior of cylinder l4. When valve 55 is moved to the right, however, by the engagement of arm 5! with cam 53. passage 55 is closed to the atmosphere except through the restricted passage 55. Only a small amount ofair is thereafter introduced into cylinder i4 through opening 23, with the result that the movement of the piston is effectively retarded and the friction surfaces of the clutch are engaged at a very slow rate of speed, the speed of this movement being dependent upon the adjustment of the bleed valve 59. After cam 53 has passed roller 52 in moving tobeing substantially par- When, however, the parts move toward:

ward normal clutch engaged position, spring 51 returns valve 55 and arm 5| to normal position, whereuponv passage 55 and cylinder N are again iuily opened to atmospheric pressure.

Under certain conditions, as when parking a vehicle, for example, it may be desirable to slip" the clutch, and under other conditions to speed up the engagement of the clutch, i. e., to render the automatic operation of valve 55 of the device inefl'ective. The mechanism above described is adapted to facilitate the control of the clutch to meet varying conditions, at the will of the operator. If it is desired to render the automatic control elements ineffective whereby clutch engagement may be speeded up when shifting from second to third gear, for example, the operator depresses rod 45 a short distance during the movement of the clutch friction surfaces toward engaged position. At this time, valve 29 is on its seat, and the vacuum of the engine is effective to resist movement of said valve from closed position. Accordingly, a slight movement of rod 45 is effective to move rod 42, member 35 and barrel 34 to the right, whereby valve 31 is unseated and air passage 4| is opened. Due to the yielding motion transmitting connection 35, 35, this movement of barrel 34 is effected without moving valve 23 from its seat with the result that air flows through passage 4|, passages 33a, past valve 35, and through opening 23 into the cylinder, whereby the engaging movement of the clutch surfaces is speeded up, and this regardless of the position of the automatically operated valve 55 and bleed valve 59.

If, after rod 45 has been released and valve 25 has -seated, it is desired to "slip" the clutch or to arrest the movement of the same in any desired position, rod 45 is depressed until spring 35 is compressed suiilciently to pull valve 29 ofl its seat against the pressure spring 36, which is reduced as barrel 34 moves to the right, and the vacuum pull on the lefthand end of valve member 25. As soon as valve 29 is unseated in this manner, the fluid pressures acting upon the various surfaces of member 25 will be equalized and the latter will move to the right (Fig. 2) to a position at which the force of spring 35 equals that of spring 35. To accomplish this, it

is not necessary to depress rod 45 sufficiently far to seat valve 35 as is done when full clutch disengagement is desired. It will be seen, therefore, that power cylinder I4 is thus opened to both atmosphere and vacuum, the mixing valve 25 assuming what" may be termed a floating position intermediate the seats for valves 25 and 35. Under this condition, member 25 will move in unison with rod 45 springs 35 and 35, the relative movement of the samebeing determined by the design of cam surface 45a. The operator, therefore, will be enabled, by manual movement of rod 46, to position mixing valve 25 so that the volume of air entering chamber 24 through passage 33a will be just suflicient to decrease the vacuum pull on piston 15 to maintain a substantial balance between such pull and the force tending to move the clutch surfaces to engaged position, thereby arresting the latter.

To maintain this established balance or equilibrium, it will be noted that the volume of air entering passage 330. must be substantially equal to that being simultaneously withdrawn through passage 21 into the intake manifold. In order to minimize the volume of air which'must thus pass by thevalves and to increase the ease of control,

through the medium of member 2| in the illustrated embodiment is provided at each end with tapered portions flu and Ila which extend into and progressively restrict or increase the port areas I! and "a, respectively, the area of one increasing as the other decreases as a result of the movement of member 2|. The degree of taper employed on portions Ila and llla is such that a comparatively small change in port area is obtained by an appreciable movement of rod 4|, thus increasing the fineness of operation. It will be seen that the operator by slight manual adiustments of rod 4| may maintain the clutch surfaces in a stationary position or, by thus increasing or decreasing the port area Isa, he may cause the said surfaces to move toward either engaged or disengaged position, respectively, in the same manner as when manual clutch operation is employed.

The complete engaging movement of the clutch may be controlled through the manual actuation of valve 2| in a manner like that above pointed out for slipping or arresting the same. This is accomplished by releasing rod 48 gradually from depressed position whereupon valve 28 assumes its floating position in chamber 24 and permits the operator to arrest, slip, or reverse the direction of movement of the clutch at will. The clutch may thus be kept under the complete control of the operator when parking or turning in close quarters.

If it is desired to control the rate of engagement of the clutch surfaces in accordance with the pressure in the intake manifold so that such rate will vary directly as the speed with which the accelerator Ila isactuated, it is only necessary to adjust valve 59 (Fig. 3) to closed position. The clutch surfaces are now disengaged in the manner previously described, and when rod 46 is released, said surfaces will move rapidlyv toward engaged position until cam 5| engages arm II, whereupon said surfaces will gradually come to rest as valve 5! is moved by said arm to the right, progressively covering ports "a and to completely cut oil the supply of air to cylinder l4. When cylinder I4 is open to atmosphere, valve 2| is held on its seat only by a very slight pressure from spring l8 and by the vacuum pull onthe face thereof. As soon as the cylinder is cut off from atmosphere by valve II, as pointed out above, valve 28 is subjected to a diflerential pressure, i. e., the diiference between the subatmospheric pressure in the intake manifold and that i cylinder I4. When accelerator lid is depressed, the pressure in the intake manifold is increased to a value in excess of that in cylinder I4, whereupon valve member 28 will move to the right to permit air from passage 21 to enter cylinder I4 past valve 29. The clutch surfaces now move into full engagement. It is a well-known fact that the pressure in the intake manifold increases in proportion to the rate at which the accelerator pedal is depressed, and it will be seen, therefore, that the rate of engagement of the clutch surfaces will vary directly as the spemi with which the accelerator is depressed. Since in normal operation of a vehicle the accelerator is depressed more quickly when shifting into high gear than when starting in low gear, proper variation in speed of clutch engagement is obtained for all gear ratios. When the clutch surfaces are engaged, cam 5| will have moved from under arm Bl, allowing spring 51 to move valve II to the left to open ports l|s and II to a ain admit full. atmospheric pressure to cylinder l4.

The mechanism of the present invention is so constructed that in the event that the power means fails, the driver may manually disengage the clutch. For this m rod4| carries a loose sleeve |l provided at its lower end with a flange l2 adapted to engage inwardly extending flanges II of a bifurcated lever II that is. pivoted to bracket II as at The outer ends '4 of lever |l are adapted to emse roller II on the opposite side from lever ll. Rod 4| also carries a rigidly attached sleeve 81. the lower end of which is normally spaced from the upper end of loose sleeve |l whereby rod 4| may be actuated to provide for power operation of the clutch without manually operating the clutch. I: the power means'fails, however, the operator depresses rod 4| a suiilcient distance to move sleeve 81 into engagement with sleeve |l. Further downward movement of rod 4| is effective through flange I2 and ears I! to swing the arm 84 in a clockwise direction whereby lever II is moved about its pivot in an anticlockwise direction and the friction surfaces of the clutch are disengaged. In spite of the failure of power or the desire of the driver to cut out the automatic disengagement,

as is desired under some circumstances, the control means heretofore described is now operative to automatically retard the clutch surfaces just prior to and during the engagement of the same. Smooth and proper clutch engagement is thus insured even when one resorts to manual operation of the clutch.

Spring 12, during normal operation of the power means, yieldingly holds lever I! in the position illustrated in Fig. 1 during operation of the power means. 5

An additional control which operates in accordance with the engine speed may be provided for valve member 2|, either alone or in combination with the manual control means heretofore described. As shown in Fig. 2, U-shaped member 3| is secured as by means ofa screw 1| to the armature ll of a solenoid II which is operatively connected by means of leads II to the generator,

or battery, of the vehicle and to a switch (not shown) positioned at any suitable point within easy access of the driver, as on top of the gear shift lever, or the same may be operatively connected to the accelerator pedal. The switch may thus be manually operated to control the de- (3111131811118 and clutching operation, instead of rod 4 In Fig. 9, there is illustrated another embodiment of the invention wherein the power unit of Fig. l is operatively connected to a clutch pedal II by means of a flexible connection I4. One end ofthe connection is secured in any suitable manner to piston rod I| while the opposite end of said connection is pinned to a strap II which surrounds clutch pedal 1| at a convenient Point. The unit is so mounted beneath the floor boards that rod 4| projects therethrough in a tion of the clutch spring 1|. When rod 4| is re-' leased, the clutch lever II and hence the friction surfaces of the clutch are returned to engaged position in the manner previously described in connection with Fig. 1. The arrangement shown in Fig. 9 is adapted for ready installation as an accessory and eliminates the necessity for the type of clutch lever shown in Fig. 1. eliminates the necessity for the bifurcated lever 65 and its associated elements, the'iunction of the latter being performed in the usual manner by clutchpedal 13.

The embodiment of the invention illustrated in Fig. 10 is quite similar to that shown in Fig. 9 but differs therefrom in that the clutch pedal 13 is connected to piston rod it by means of a rigid rod Ill. Preferably, a ball and socket connection Bl forms the connecting means between rod 80 and piston rod It. By this arrangement the retarding means constituted by the power unit, lever El and cam 53. are effective to impart a variable movement to the clutch surfaces as the latter move to engaged position. If desired, a ball check valve 82 may be provided for piston I! to insure that the operator will not have to work against compression within cylinder ll during manual operation of pedal 13.

There is thus provided novel clutch mechanism adapted for power or manual operation. In one embodiment of the invention, a single member is employed for initiating operating of the power unit and, in the event that the latter fails to function, said member may be actuated manually to operate the clutch in the usual manner. The mechanism is so constructed as to insure prompt and smooth engagement of the friction surfaces of the clutch, thereby eliminatin the care and skill usuall required on the part oi an operator. Unusual flexibility is provided for in that the clutch can he "slipped," the movement of the clutch elements into engagement may be arrested, reversed or speeded up, thereby rendering the automatic engaging means ineffective, and, finally, the speed of engagement of the friction surfaces of the clutch may be varied in accordance with-the changes in pressure in the intake manifold. As will be understood by those skilled in the art, if power operation of the clutch is not desired, automatic control of the engaging movement of the friction surfaces of the clutch may still be maintained.

The mixing valve 26 is associated with means for securing two-stage movement of the clutch surfaces to engaged position. when valve 29 is moved a short distance from its seat, additional air will bleed past valve 31 to supplement the air flowing past bleed valve 59, whereby the second stage of the movement may be speeded up, if desired. Under certain conditions, manually operable valve 26 may be power operated by the difference in pressures on the opposite sides thereof, or said valve may be operated by the power means 88.

Various changes may be made in the details of construction and in the arrangement of parts. and reference will accordingly be had to the appended claims for a definition of the limits of the invention.

What is claimed is: y

1. Apparatus of the character described comprising a power device connected to an operating member of a motor vehicle clutch having a normal bias to operative position, a control device for rendering the power device operative to move the clutch elements to inoperative position and releasable to permit the clutch elements to return to normal position, and automatic means rendered operative as the elements of the operative position for retardclutch approach ItBlSO' ing the movement of such elements, said control device including an element controllable to render said automatic means substantially ineflective for retarding the clutch elements.

- 2. The combination with a motor vehicle clutch and an operating member therefor, of a'power device connected to said operating member and operable for disengaging the clutch, a control device movable from normal position for rendering said power device operative, and automatic means operative as the elements of the clutch approach operative position for retarding the movement of such elements said control device including means for rendering said automatic means substantially ineffective for retarding the clutch elements.

3. The combination with a motor vehicle clutch having a normal bias to operative Dosition and an operating member therefor, of a power device connected to the operating member, a control device for rendering the power device operative to move the clutch elements to inoperative position and releasable to permit the clutch elements to return to normal position, and automatic means rendered operative as the elements of the clutch reach approximately the point of initial engagement for checking the movement of such elements, said control device including an element controllable to render said automatic means substantially inefiective for checking the movement of the clutch elements.

4. The combination with a motor vehicle clutch having a normal bias to operative position, of a-power device including a chamber having a member therein operative by differential pressure and connected to the clutch, valve mechanism normally operative for establishing pressure equalization in said power device and opera-ble for establishing pressure differential therein, and an automatic valve operative in conjunction with said valve mechanism for checking the movement of the clutch elements as they reach approximately the point of initial engagement, said valve mechanism being subject to control independently of said automatic valve for rendering the latter ineffective for substantially retarding the movement of the clutch elements.

5. Apparatus of the character described comprising a power device including a chamber having a member therein operative by difierential pressure and connected to a motor vehicle clutch having a normal bias to operative position, valve mechanism normally operative for establishing pressure equalization in said power device and operable for establishing pressure differential therein, and an automatic valve operative in conjunction with said valve mechanism for checking the movement of the clutch elements as they reach approximately the point of initial engagement, said valve mechanism being subject to control independently of said automatic valve for rendering the latter ineffective for substantially retarding the movement of the clutch elements.

6. Apparatus of the class described comprising a power device connected to' an operating member of a motor vehicle clutch, control means including a floating valve for rendering said power device operative to move the clutch surfaces to inoperative position and for releasing the clutch surfaces for movement toward operative position, means operative as the clutch surfaces approach engaged position for retarding the movement of said surfaces, moving said clutch surfaces to inoperative position, said retarding means belns operative inand manual means for dependently of whether the clutch surfaces are moved to inoperativ position by said power device or by said manual means.

7. Apparatus of the class described comprising a power device connected to an operating member of a motor vehicle clutch, control means including a manually operable member and a floating valve adapted for movement relative to said manually operable member, said control means being adapted to render the power device operative to move the clutch surfaces to disengaged position and for releasing the clutch surfaces for movement toward operative position, and means for varying the rate of movement of the clutch surfaces as they approach operative position, said control means being adapted to render the last-named means ineffective.

8. In a pneumatic apparatus for actuating the clutch lever oi a motor car, the combination with such clutch lever of a cylinder having a closed end, a piston in said cylinder having a piston rod extending through an end of said cylinder and connected to said lever, a conduit connected to the interior of the closed end of said cylinder, and a valve apparatus controlling passage through said conduit comprising a valve casing to which such conduit is connected, and a valve member having a sliding fitin said casing and also having a relatively considerable portion of its length of a slightly tapering crosssection adapted to cooperate with a port in said casing during a portion of its travel whereby the now of'air from said closed end of the cyiinder may be regulated by adjustment of such valve member with reference to said port.

9. In apparatus of the class described, a friction clutch, a lever for moving the friction surfaces of said clutch to disengaged position, said lever being adapted for manual operation, means for moving said lever from disengaged position to engaged position, and means for controlling movement of the lever toward clutch engaged position whereby said lever has rapid movement prior to engagement of the friction surfaces of the clutch and a substantially retarted movement immediately prior to and during engagement of said friction surfaces, said last named means including valve means" controlled in accordance with the movement of said lever and means for rendering said control means ineffective during clutch disengaging movement of said lever.

10. In apparatus of the class described, a fluid pressure operated device, differential pressure valve means for controlling said device, and manual means connected to the valve means for rendering the pressure control of the first-named means ineffective.

11. In apparatus of the class described, a friction clutch, a lever for moving the friction surfaces of said clutch to disengaged position, means operatively connected to the lever for holding the friction surfaces of the clutch in engagement and for moving the lever from disengaged position to engaged position, fluid pressure means for variably controlling movement of the levertowards clutch engaged position including a fluid pressure cylinder, a piston thereon, and movable air control means operatively connected to said piston, and means for rendering said control means ineffective during clutch disengaging movement of said lever.

.12. The combination in a motor vehicle of a clutch, means for normally holding said clutch in engaged posiiionjmanually operable means for disengaging said clutch, means for controlling the speed of engagement of said clutch by said first-named means including a member movable with said manually operable means, and valve means controlled in accordance with the position of said member, and means for rendering said control means ineffective during disengaging movement of the clutch.

13. In apparatus of the class described, a fluid pressure device having a movable member, means for moving said member in one direction, and means for controlling said device comprising a mixing valve and means controlled by said memher for subjecting the latter to an irregular movement.

14. In an automotive vehicle provided with a clutch, a pressure diflerential operated motor for actuating said clutch, and, valve means for controlling said motor including a power operated valve for initiating the clutch disengaging and engaging operations of the motor, and independently operable manual means for actuating said power actuated valve.

15. In a clutch control device for motor vehicles, a power device connected to the clutch capable of releasing it, a control device for the power device to cause it to function to release the clutch, and automatic means controlled by movement of the clutch to irregularly controlsaid power device in the engagement of the clutch, said control device comprising manually operable means for markedly modifying the action of said automatic means automatically ad- Justed during any one clutch engagement movement by a person seated in such vehicle.

16. In a pressure difl'erential operated power clutch control device for motor vehicles, a power actuator including stationary and movable members, said movable member being connected to the clutch for effecting disengaging movement thereof, manually operable means for controlling the clutch disengaging and engaging operations of the power actuator and means for controlling said power actuator to eflect an irregular engaging movement of said clutch, said first-mentioned means including means for rendering said second-mentioned means ineffective thereby permitting a substantially uniform clutch engagement.

17. Apparatus of the character described comprising a differential pressure power device operatively connected to a motor vehicle clutch, a valve device movable in one direction for connecting the power device to a source of differential pressure and movable in the opposite di rection for disconnecting the power device from the source of differential pressure and connecting it to the atmosphere, means operative when the clutch elements reach an intermediate position substantially at the point of initial engagement for rendering the valve device ineffective for connecting the power device to the atmosphere whereby movement of the clutch elements will be checked, and means operative for reestablishing pressure equalization in said power device to permit the clutch elements to move into engagement with each other after they have been checked in such intermediate position. a

18. Apparatus of the character described comprising a differential pressure power device operatively connected to a motor vehicle clutch, a valve device for connecting the power device to a source of differential pressure and for disconnecting the power device from the source of differential pressure and connecting it to the prisina a diflerentiai eater 19. Apparams of the character described compressiue power device opto a motor vehicle clutch, a for ecnnectina the power device to diflerential pressure and ior disconthe source oi eratively valve device a source 01' neetinl the power device from diflerential pressure endecnnectinzittotheatmosphere, means operative when the clutch elements reach an intermediate position for renderinz the valve device ineffective for connect- 5 in: the power device to the atmosphere whereby movement or the checked, pressure means merit for controlling clutch elements other.

clutch elements will be operative for reestablishing equalization in said power device to permit the clutch elements with each other after they have been checked in such intermediate position,

the rate of movement of the to move into engagement with each CHARLESABREWER 

